Technologies exist to detect and measure CO2 volumes, concentrations and fluxes in deep geologic, shallow subsurface, marine and atmospheric environments. These technologies include seismic, electromagnetic, gravimetric, geochemical, geophysical and optical methods. Principal among the applications of these monitoring technologies are: (1) enhanced oil recovery operations and (2) measurement of CO2 emissions from natural landscapes to quantify emissions due to landscape use and to demonstrate compliance with international agreements. There is, in addition, an emerging application for Monitoring, Measurement and Verification (MMV) of CO2 geosequestration sites both during injection and during long term storage periods.
Existing technologies are not well suited to measurements at densely spaced, shallow sub-surface sampling sites, the detection and monitoring of CO2 fluxes from the vadose zone to the atmosphere the identification of leaks along wellbores the detection of dissolved CO2 seepage into subaqueous environments and the detection of leakage during injection or post-injection from subsea wells and formations. In addition to these deficiencies, the capital and operating costs of conventional MMV technologies for geologic CO2 storage are impractically high. Thus, current methods cannot be economically deployed for distributed MMV of many of the possible leakage paths for CO2 in geologic storage, and improved approaches are needed.